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Fix #14891 FP knownConditionTrueFalse (dereferencing pointer to array member) #8704

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Fix #14891 FP knownConditionTrueFalse (dereferencing pointer to array member) #8704

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9549ab6
Update vf_analyzers.cpp
chrchr-github Jul 7, 2026
232bbf4
Update testvalueflow.cpp
chrchr-github Jul 7, 2026
926fe38
Update vf_analyzers.cpp [skip ci]
chrchr-github Jul 13, 2026
076bafd
Update valueflow.cpp
chrchr-github Jul 13, 2026
ccd2c28
Update valueflow.cpp
chrchr-github Jul 13, 2026
91832cc
Check op1
web-flow Jul 24, 2026
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2 changes: 2 additions & 0 deletions lib/valueflow.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -3606,6 +3606,8 @@ static void valueFlowSymbolic(const TokenList& tokenlist, const SymbolDatabase&
continue;
if (tok->astOperand2()->exprId() == 0)
continue;
if (tok->astOperand2()->variable() && tok->astOperand2()->variable()->isArray() && tok->astOperand2()->variable()->getTypeName() != "std::array") // array to pointer decay

@pfultz2 pfultz2 Jul 24, 2026

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Should also check its being assigned to a pointer: astIsPointer(tok->astOperand1()).

Also I dont really see the point in checking for std::array, and its probably better to not check just in case a future version of C++ add implicit conversions to support pointer-like decaying behavior.

@pfultz2 pfultz2 Jul 24, 2026

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Actually even better would be to compare the pointer rank if it matches: tok->astOperand1()->valueType().pointer != tok->astOperand2()->valueType().pointer

continue;
if (!isConstExpression(tok->astOperand2(), settings.library))
continue;
if (tok->astOperand1()->valueType() && tok->astOperand2()->valueType()) {
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9 changes: 9 additions & 0 deletions test/testvalueflow.cpp
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Expand Up @@ -9092,6 +9092,15 @@ class TestValueFlow : public TestFixture {
" return x;\n"
"}\n";
ASSERT_EQUALS(false, testValueOfX(code, 3U, "malloc(10)", 0));

code = "struct S {\n" // #14891
" void f() const {\n"
" const int* p = a;\n"
" if (*p) {}\n"
" }\n"
" int a[3];\n"
"};\n";
ASSERT(tokenValues(code, "* p )").empty());
}

void valueFlowSymbolicIdentity()
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